Specifications

72 Intel
®
Atom™ processor CE4100 Ref# 420826
Platform Design Guide
Intel Confidential
Figure 6-4. VBG_EXTR_VDAC Connection
Figure 6-4 provides an illustration of the recommended shielding trace connection. 75 Ω is
ach
ievable by routing microstrip on layer 1 while referring to layer 3.
6.1.1.4 Video DAC Trace Separation
Use the following separation guidelines for the Video DAC interface. Figure 6-5 provides an
illustration of the recommended trace spacing.
• Maintain parallelism between VDAC_P and VDAC_N signals with the trace spacing
needed to achieve 37.5 Ω ± 10% single-end impedance from the processor to the
termination resistor.
• It is not necessary to maintain parallelism, while trying to keep as big space as possible
between _P and _N.
• Deviations will normally occur due to package breakout and routing to connector pins.
Ensure that the amount and length of the deviations are kept to the minimum possible.
• Use an impedance calculator to determine the trace width and spacing required for the
specific board stack-up being used.
• Based on simulation data, use 108-mil minimum spacing between the Video DAC
signals, and other signal traces for optimal signal quality. This helps to prevent
crosstalk.
Figure 6-5. Illustration of Video DAC Trace Spacing